The present invention relates to forming a charge-containing element, which is useful as a capacitor or as a toner-receiving roller.
Ceramic oxide layers are diverse in their properties. Apart from their unusually high mechanical strength, high wear and abrasion resistance, and high corrosion resistance, they can be considered to be dielectric, ferroelectric, piezoelectric, or optoelectronic materials. They can also be utilized in both electrical and thermal insulation applications. These ceramic oxides can be crystalline or amorphous.
Layers of ceramic materials can be manufactured using physical vapor deposition (PVD) and chemical vapor deposition (CVD), laser ablation, dip and knife coating of a ceramic precursor material, and metallo-oxide decomposition (MOD) as shown by Mir et al in commonly-assigned U.S. Pat. No. 4,880,770.
Formation of dielectric material normally requires high temperature processing. This high temperature processing restricts the choice of substrates that can be selected for use. Capacitors are multilayer coatings comprised of an arrangement of conductive, dielectric, and conductive layers in sequence. There is a need for forming dielectric materials on a substrate in many applications such as capacitive devices. Capacitors are essentially materials with high dielectric constants. Dielectric (which is essentially electrically non-conducting) characteristic of ceramic materials are well known and getting increasing importance as the field of solid state electronics continues to expand rapidly. The principal applications for ceramic dielectrics are as capacitive elements in electronic circuits and as electrical insulation. For these applications, the properties of most concern are the dielectric constant, dielectric loss factor, and dielectric strength. The principal characteristics of a capacitor are that an electric charge can be stored in that capacitor and the magnitude of the charge which can be stored is dependent primarily on the nature of the material, grain size, and the impurity distribution at the grain boundaries.
It is an object of the present invention to provide an improved charge-containing element such as a capacitor or toner-receiving roller.
This object is achieved in a charge containing element comprising:
(a) a conductive layer;
(b) a dielectric layer formed on the conductive layer wherein the dielectric layer is formed by the thermal decomposition of an organic component of the dissolved metallo-organic material and a reaction of the metallic portion of the material with oxygen thereby causing the dielectric layer to have charge holding properties; and
(c) electrodes coupled to the element to permit the application or discharge of charge from the dielectric layer.
The present invention is particularly suitable to provide a dielectric layer for a charge receiving element such as a capacitor or a toner receiving roller that can be produced at a low temperature so that the substrates are not adversely affected by the process of formation of the charge receiving element.
This invention provides a convenient way to have fully completed solid state reactions to produce desired chemistries in material layer. It is easy to control various crystallographic phases of the material by simplified doping methods.
The dielectric layer can be made with low cost deposition equipment, and permits excellent control of overall stoichiometry, high uniformity of thickness and composition, and ability to coat irregular substrate shapes in a cost effective manner.
This invention overcomes many of the problems that are associated with conventional methods of fabricating multilayer capacitors, flexible capacitors, scratch resistant lenses, capacitors integrated onto circuit boards, and protective coatings on metals, alloys, polymers, organics, inorganics, composites, glasses, paper, photographic film, magnetic media, and ceramic substrates both flexible and rigid in form.